This invention relates to a belt noise control mechanism for use in a wide variety of machines, for example, copier/printers.
Excessive noise from machines, such as, copier/printers in working environments has been an irritant to users from the advent of such machines until the present day. One of the major contributors to machine noise has been found to be idlers of timing belt systems. At low speed, noise from idlers is as high as that of the timing belt and pulley system combined. At higher speeds, the noise level of an idler has been found to be an order of magnitude higher as shown in FIG. 1. This is because typical idler systems found in copiers, printers, duplicators, etc., will not only generate noise, but tend to transmit and in some cases amplify the vibratory energy of the belts to the machine frame and covers. This undesirable mechanical energy is radiated as noise. A need clearly exists for a means to control noise in machines.
Noise and vibration problems are caused by tolerance build up and variations in materials among the moving parts. To name some of them, they are as follows: non-concentric of the drive shafts, non-concentric of the pulley, variations in the teeth of the pulleys and imperfections in the belts. Imperfections in the belts may include waviness at the back of the belt, variations in belt thickness due to a seam, variations in belt thickness due to molding process or variations in the belt teeth. As a result, this will induce random motion to the belt tensioning device. Excessive noise and vibration will be generated and transmitted to the frame of the machine through the belt tensioning device.